The structure of the light scalar mesons and QCD sum rules

The structure of the light scalar mesons is elucidated by the investigation of the S-matrix poles and the q-qbar spectral density in a coupled channel model that includes pi-pi, K-Kbar and q-qbar channels. It is shown that the dynamical origin of the sigma and f0(980) mesons is consistent with the observed spectrum of the scalar states. The K-Kbar molecular picture of the f0(980) is in good agreement with recent experimental data on the decay phi - gamma pi pi from Novosibirsk.